I can understand your concern, but that's why the magazine is free. The same goes for eWeek, InternetWorld, Web Hosting Magazine and any other industry magazine.
These magazines can afford to send out the magazines for free because they can tell advertisers their readers are a great demographic market segment that can onyl be reached through their magazine. The only way they can do that is by quizzing their readers when they signup.
I always lie when I fill out the questionnaires anyway.
Being a one-person shop, I'm President, decision-maker on all purchases on all hardware and software in practically all categories, guide my company in all areas of internet business management, etc. I say my business has "less than 10 people" (I'm not lying). The only thing I exaggerate is the size of my revenues and my planned purchases and investments each year. Unless you work for one of the big companies, I think everybody does the same.
Besides, they do not sell away your information, but only aggregate it internally to help mark up their advertising rates.